[QP] When querying a bare model with parameters, wrap an extra stage (#39963)

This matches how models are visualized, and how the parameters are
attached to them in the first place - an extra ad-hoc query is wrapped
around the model.

Because of that wrapping, a parameter will be targeting a model's field
by name rather than by ID, but that parameter cannot be applied directly
on the model's last stage.

Fixes #39940.